43 lines
1.4 KiB
Diff
43 lines
1.4 KiB
Diff
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Thu, 11 Oct 2018 09:07:31 +0200
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Subject: [PATCH FIX] spi: bcm-qspi: switch back to reading flash using smaller
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chunks
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Fixing/optimizing bcm_qspi_bspi_read() performance introduced two
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changes:
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1) It added a loop to read all requested data using multiple BSPI ops.
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2) It bumped max size of a single BSPI block request from 256 to 512 B.
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The later change resulted in occasional BSPI timeouts causing a
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regression.
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For some unknown reason hardware doesn't always handle reads as expected
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when using 512 B chunks. In such cases it may happen that BSPI returns
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amount of requested bytes without the last 1-3 ones. It provides the
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remaining bytes later but doesn't raise an interrupt until another LR
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start.
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Switching back to 256 B reads fixes that problem and regression.
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Fixes: 345309fa7c0c ("spi: bcm-qspi: Fix bcm_qspi_bspi_read() performance")
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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Cc: stable@vger.kernel.org # 4.11+
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---
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drivers/spi/spi-bcm-qspi.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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--- a/drivers/spi/spi-bcm-qspi.c
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+++ b/drivers/spi/spi-bcm-qspi.c
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@@ -88,7 +88,7 @@
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#define BSPI_BPP_MODE_SELECT_MASK BIT(8)
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#define BSPI_BPP_ADDR_SELECT_MASK BIT(16)
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-#define BSPI_READ_LENGTH 512
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+#define BSPI_READ_LENGTH 256
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/* MSPI register offsets */
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#define MSPI_SPCR0_LSB 0x000
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